There's theory going around in some circles, which I vehemently disagree with, suggesting the Democratic Party can permanently succeed without the South.
While I believe the Dems need to spend more time in the South and the GOP needs to invest more effort along the coasts, there is some merit to concentrating (but not limiting) resources in particular areas.
A recent story in The New Yorker looks at Colorado as a case study of how the Dems have succeeded in the West and how it might serve as a template for nationwide success.
The socially conservative wing of the GOP overreached in Colorado. A paramount focus on social issues and an unwillingness to bend on even the pragmatic virtue good government can do left many Coloradoans uneasy with the GOP. Westerners tend to be libertarian on social issues and while they may not like gay marriage they'd rather legislators fully fund education than worry about whether Tom and Harry can marry.
Today, Colorado has a Democratic governor and state legislature. Dems now talk about a green environment: a way to be both environmentally friendly and pro-business at the same time. Not pressing on social issues and developing a pro-family reputation have provided big dividends for Western Democrats.
The problem for Dems in the South is race. The West does not have race hanging around every public policy issue the way it does in the South. The trick for Dems is to keep its African American base while appealing to the growing number of Southerners (typically Northerners-moved South) that don't believe government is the enemy (per Reagan) but instead believe government (if used wisely and efficiently) can be part of the solution. Dems won't ever win social conservatives, but if they can keep blacks and better appeal to non-evangelical professional whites, the Dems can be competitive in Dixie.